Now we're announcing the next step for our project," wrote Chris Urmson, the director of the Google self-driving car project in a blog post. "This summer, a few of the prototype vehicles we've created will leave the test track and hit the familiar roads of Mountain View, Calif., with our safety drivers aboard."

According to the software giant, the cars will come with their own dedicated safety drivers, as well as a removable steering wheel, accelerator pedal, and brake pedal, which will allow them to take control of the vehicle if necessary.

The new prototypes will drive with the same software that our existing fleet of self-driving Lexus RX450h SUVs uses," continued Urmson. "That fleet has logged nearly a million autonomous miles on the roads since we started the project, and recently has been self-driving about 10,000 miles a week.